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iVinArrow [24]
3 years ago
6

Mark bought 12 boxes of paper clips and 10 packages of index cards for a

Mathematics
1 answer:
Nata [24]3 years ago
8 0

Answer:

paper clips = $1.85

index cards = $3.95

Step-by-step explanation:

Mark

12 paper clips = x

10 index cards = y

$61.70 total

Janice

15 paper clips = x

7 index cards = y

$55.40 total

12x + 10y = 61.70

15x + 7y   = 55.40

*** you want to cancel out one of the letters

(12x + 10y = 61.70) * -7

(15x + 7y   = 55.40) * 10

-84x -70y = -431.9

150x + 70y = 554.0

150x + 70y = 554.0

-84x -70y = -431.9

66x + 0 = 122.1

66x = 122.1

x = 122.1 ÷ 66

x = 1.85

plug it back in

15(1.85) + 7y   = 55.40

27.75 + 7y   = 55.40

7y   = 55.40 - 27.75

7y = 27.65

y = 27.65 ÷ 7

y = 3.95

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Answer:

24 ounces

Step-by-step explanation:

Here's a more intuitive approach to use here.

You know that your initial solution has a percent concentration, presumably volume by volume, of  

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The target solution must have a concentration of  

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Your starting solution has a volume of  

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In order to get to a solution that has a total of  

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⋅

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7 0
3 years ago
What is the slope of a line perpendicular to the line whose equation is y = 2x+5?
zubka84 [21]

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Step-by-step explanation:

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y = 2x + 5 is in this form with slope m = 2

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4 0
3 years ago
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4 0
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Michael is 4 years younger than twice his cousin, Damien’s age. The sum of their ages is 46. How old is Damien?
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4 0
3 years ago
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6 0
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